Bit extension



. May 13, 1930. J. H. ABRAMSN 1,753,069

BIT EXTENSION Filed Jan. 25, 1928 Jay. Z

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By n z f J "ZZ il c Nanay Patented May 13, 1930 UNITED STATES PAT-T loli-"Flor JOHN HERBERT ABRAMSON, F ROCKFOBD, .ILLINOIS ASSGNOR TQ GBEENLEEBRQS: & C0 0F RQCKFOED, LLNOIS, A CORPORATEON 0F lLLINOS Brr EXTENSION Application filed January 25, 1928. Serial No. 249,387.

This invention relates to improvements in bit extensions.

Bit extensions available in the past have invariably been more or less large and cumbersome in construction, so much so that they were practical only for heavy duty work. It is, therefore, an important object of my invention to provide a bit extension of a new and improved design and construction where lo the over-all diameter of the coupling parts is kept to a minimum size consistent with the requisite strength and accuracy in boring, thus making it practicable to provide bit eX- tensions suitable for light duty as well as heavy duty,

Another serious objection to prior types of bit extensions has been the inability to lock the bit with the extension in a positive manner to avoid any danger of the Asaine loosening or even becoming unfastened, especially in the retr-acing of the bit from a hole, it having been found that most bit extensions provided in the past made no provision for preventing the turning loose of al threaded d part of the coupling or chuck. lt 1s, therefore, another obj ect of my invention to avoid the objection just noted by providing an absolutely positive lock, an especially advantageous feature of which lies'in the 'fact that the same can be set in an inoperative out of the way position during the insertion or removal of a bit and, therefore, does not in any way hamper the workman in the performance of said operations.

It is moreover an important object of my invention to provide a bit extension using comparatively few parts, all of which arel of a simple form and may be produced at. very low cost, the same being for the most part capable of production on automatic screw machines.

The invention is illustrated in the drawing in two forms for light and heavy duty workl Figure l being an elevational view of the light duty bit extension of my invention;

Fig. 2 a longitudinal central section on an enlarged scale of the extension bit shown in Fig. l;

Fig. 3 a similar section of theheavy duty type;

Fig. 4 an elevational detail of a part ofthe bit extension shown in Fig. 3 to illustrate the lock, the parts of which are shown in unlocked position with the lock-ing collar set in an inoperative out of the way position;

Fig. 5 a cross-section on the'line 5 5` of Fig. l;

Fig. 6 a cross-section on the line 6 6 of Fig. 3 omitting the bit; and

Fig. 7 a view corresponding to Fig.Vv 6 with the chuck parts arranged to lpermit the insertion of a bit or the removal thereof.

Similar reference numerals are applied to corresponding parts throughout the views.

Referring first more particularly to Figs. l and 2 wherein I have. illustrated my light duty type bit extension, it will be observed that the same comprises a shank 8 of suitable length with a squared tapered end Y9 adapted for insertion in the chuck of an ordinary brace or motor driven tool, and having coupling means l() on the other end thereof for the secure holding `and locking of a bit 11, the squared and tapered end 12 of the latter being arranged for detachable connection with the bit extension somewhat similarly as the squared and tapered end 9 of the shank 8 is arranged for detachable connection with the brace. My invention is particularly concerned with improvements in the design and construction of the coupling means 10, vit being, as stated above, one im-f portant object of my invention to keep 1the over-all diameter of the coupling to a minimum consistent with the required strength and accuracy in boring, and another object to lock the coupling with the bit in an absolutely positive manner so that there is never any danger of the bit loosening or becoming unfastened, especially in the backing out of the bit from a hole. According to my inven tion the shank 8, which is preferably in the form of an ordinary cylindrical rod, has a portion '13 of slightly reduced diameter where it passes through the locking collar lli, to which further reference will be made presently, thus providing an annular shoulder at l5. Then, where it enters the sleeve 16 of the coupling proper, the shank is further reduced in diameter, as shown at 17, thus affording another annular shoulder at 18 to abut the end of the sleeve 16 and hold the same against movement in one direction. The extremity of the reduced end portion 17 of the shank 8 is received in a tubular chuck member 19 and fastened thereto suitably by a pin 20, only one end of which, the end which appears in the two views, being left extending from the outside of the chuck member 19. The latter serves by abutment with the adjoining end of the sleeve 16 at 21 to confine the sleeve against movement away from the shoulder 18 while permitting rotation thereof when the same is not locked by the collar 14, as will presently appear. A socket 22, complementary in form to the tapered squared end of the bit 11, is provided in the chuck member 19. The socket 22 illustrated in Figs. 3, 6, and 7 provided in the heavy duty type bit extension is of corresponding form. The bit is arranged to be held in place in its socket by the wedging engagement therewith of inclined shoulders 23 provided in the end of an outer sleeve 24, the shoulders 23 being afforded between the square opening 25 in the end of the sleeve 24 and the cylindrical bore 26 of said sleeve. These shoulders correspond to the shoulders 23 provided in the sleeve 24 of the heavy duty type bit extension shown in Fig. 3 where said shoulders are provided between the square opening 25 and the cylindrical bore 26. The method of holding the bit is, therefore, the same in both cases and the illustrations in Figs. 6 and 7 serve for both forms. It will be evident that the end 12 of the bit may be entered through the hole 25 for insertion into the socket 22 when the opening is disposed with reference to the socket, as shown in Fig. 7, but that when the sleeve 24 (or by analogy the sleeve 24) is turned clockwise through 45o to the position shown in Fig. 6 the bit is held against removal from the socket to cause engagement with the shoulders 23. I claim no invention in this particular type of chuck excepting only in so far as the same cooperates as a part of the novel combination and arrangement of parts herein disclosed. The sleeve 24 is interlocked with the chuck member 19 by means of the pin 2O which has the projecting end thereof received in a bayonet slot 27 provided in the sleeve 24. The sleeve 24 is also internally threaded, as appears at 28, to receive the externally threaded reduced portion 29 of the sleeve 16. rThe latter is knurled, as appears at 30. to facilitate the turning thereof by hand. lVhen the pin 20 is in the longitudinally extending portion of the slot 27 the sleeve 24 is manifestly held against turning with respect to the chuck member 19 and hence also with respect to the shank 8 with which the chuck member is rigid. Since the sleeve 24 is held against turning, the turning of the sleeve 16 causes endwise movement of the sleeve 24 by reason of the interthreading 0f said sleeves. The turning of the sleeve 16 in one direction extends the sleeve 24 until the pin 2O arrives at the end of the slot 27 where, because of the provision of the transversely extending portion of the slot, the sleeve 24 is free to be turned through approximately 45 either to permit the removal of a bit or the insertion of one. TiVhen the pin is in the longitudinally extending portion of the slot the sleeve 24 is in the position represented in Fig. 6 and when the pin is at the end of the slot and the sleeve is turned through 45o it is thereby brought to the position shown in Fig. 7. The coupling afforded by the novel construction and arrangement just described affords the practical advantage that the over-all diameter is kept absolutely to the smallest size without sacrificing strength or rigidity.

The locking collar 14, previously referred to, has a slot 31 in the end thereof adjoining the end of the sleeve 16 arranged to receive the projecting end of a pin 32 driven into a hole drilled through the portion 13 of the shank 3 to hold the collar against turning with respect to the shank. The collar is normally urged toward the pin 32 by a coiled compression spring 34 acting between the annular shoulder 15 on the shank 8 and an annular shoulder 35 provided in the bore of the collar 14. The end of the sleeve 16 adjoining the collar 14 is castellated to provide a series of circumferentially spaced notches 36 in which one or more lugs 37 provided on the collar 14 are arranged to engage when the pin 32 is engaged in the notch 31. 1t is evident that since the collar 14 is held against turning with reference to the shank 8 by the pin 32, the sleeve 16 is likewise held against turning when the lugs 37 are engaged in the notches 36 thereof. The collar 14 is knurled, as indicated at 38, to facilitate the handling' thereof as, for example, when it is desired to unlock the extension by re tracting the lugs 37 from engagement in the notches 36. The collar 14 is thereby released from the pin 32 and may then be turned to a position where the slot 31 is thrown out of alignment with the pin, whereupon the pin is arranged to hold the collar in an out of the way inoperative position by engagement with the end thereof. rlhe slot 31, it will be observed is of suiiicient depth as compared with the length of the lugs 37 that the latter have ample clearance between the same and the castellated sleeve 16 when the collar 14 is held by the pin 32 in its inoperative position. There'is nothing, therefore, to hamper the workman in the turning of the sleeve 16 for the insertion or removal of a bit. Thile the lock just described is of exceedingly simple and economical eonstruction I do not wish to limit myself to the use of this or any other special kind of lock.

In the construction of the heavy duty type bit extension, as shown inv Fig. 3, I prefer not to reduce the size of the shank 8 at any point in the coupling 10 so as not to sacrifice strength. rIhe shank 8 has an enlarged end 19 which is recessed in the end thereof to provide the socket 22 for the reception of the end 12 of the bit 11. The sleeve 24 cooperates with the chuck portion 19 for the holding of the bit, as in the other form, and has a pin 20 corresponding to the pin 20 of the other form received in a bayonet slot therein corresponding to the slot 27. The sleeve 16 serves the same function as the sleeve 16 and is retained in place on the shank 8 in engagement with the annular shoulder 21 by a sleeve 13 pinned on the shank 8, as indicated at 39. The operation of the sleeve 24 back and forth with respect to the shank 8 by the turning of the sleeve 16 is, therefore, the same in this form as in the other. rPhe locking collar 111 cooperates with the sleeve 16 in practically the same way as the collar 14; cooperates with the sleeve 16, the only difference being that in place of the pin'32 a short pin 32 is pr-ovided, the extending end of which is received in a slot 31 cut in the inside of the collar 14;. The lugs 37 in this form cooperate with the notches 36 in the end of the sleeve 16 in the same way as in the other form.

It is believed the foregoing description conveys a clear understanding of my invention and of its various objects and advantages. lVhile the invention has been illustrated and described in connection with two embodiments it is evident that modifications may be made without seriously departing from the spirit and scope of the invention as more or less clearly defined by the appended claims.

I claim:

1. In a bit extension the combination with an extension shank having a chuck on the one end thereof arranged for detachably holding a bit, and a sleeve member fitting on said shank at the chuck end and arranged to be turned in one direction in the opening of the chuck and in the opposite direction in the closing thereof, of means for detachably locking the sleeve member against turning with respect to the shank comprising a locking collar on the shank adjacent the end of said sleeve, said collar having an Outside diameter preferably of substantially the same outside diameter as the sleeve for the purpose herein contemplated, a coiled compression `spring fitting about the shank and bearing at one end against an annular shoulder provided on a xed part of the shank and at the other end against an annular seat provided therefor on the collar whereby to urge the collar yieldingly toward the sleeve, means serving to hold the collar against turning relative to the shank but permitting the collar to be retracted from the sleeve against the action of the spring, and projections and recesses provided on the abutting ends of the sleeve and vcollar adapted to interfit when the collar is in locking position whereby to hold the sleeve against turning relative to the shank.

2. In a bit extension the combination with an extension shank having a chuck on the one end thereof arranged for detachably holding a bit, and a sleeve member fitting on said shank at the chuck end and arranged to be turned in one direction in the opening of the chuck and in the opposite direction in the closing thereof, of means for detachably locking the vsleeve member against turning with respect to the shank comprising a locking collar on the shank adjacent the end of said sleeve, said collar having an outside diameter preferably of substantially the same outside diameter as the sleeve for the purpose herein contemplated, a coiledcompression spring fitting about the shank and bearing at one end against an annular shoulder provided on a fixed part of the shank and at the other end against an annular seat provided therefor on the collar whereby to Yurge the collar yieldingly toward the sleeve, a pin driven into a transverse hole pro-vided in the shank with the end thereof projecting from the shank, said collar having a slot provided in the wall thereof arranged when the collar is turned to a certain position to receive the pin, whereby to hold the collar against turning relative to the shank, said collar being arranged to be retracted from the sleeve against the action of the spring and to be turned to throw the slot out of alignment with the pin whereby the pin serves to hold the collar in retracted position, and projections and recesses provided on the abutting ends of the sleeve and collar adapted to interit when the collar is in locking position whereby to hold the sleeve against turning relative t0 the shank.

3. In a bit extension the combination with an extension shank having a chuck on the one end thereof arranged for detachably holding a bit, an outer sleeve mounted for endwise movement on the end of said shank and cooperating with the chuck so that the same is moved in one direction in the opening of the chuck and in the other direction in the closing thereof, and an inner sleeve held against endwise movement on the shank behind the outer sleeve but normally free to turn, said inner sleeve being externally threaded for cooperation with the internally threaded end of the outer sleeve whereby in the turning of said inner sleeve in one direction the outer sleeve is moved in a certain direction and vice versa, of means for detachably locking the inner sleeve against turning with reference to the shank comprsing a locking collar on the shank adjacent the end of said sleeve, said collar having an outside diameter preferably of substantially the same outside diameter as the sleeve for the purpose herein contemplated, a coiled compression spring fitting about the shank inside the collar bearing at one end against an annular shoulder provided on a fixed part of the shank and at the other end against an annular shoulder provided on the inside of the collar whereby to urge the collar yieldingly toward the sleeve, a pin driven into a transverse hole provided in the shank with the end thereof projecting Jfrom the shank, said collar having a slot provided in the Wall thereof arranged when the collar is turned to a certain position to receive the pin, Whereby to hold the collar against turning relative to the shank, said collar being arranged to be retracted from the sleeve against the action of the spring and to be turned to throw the slot out of alignment with the pin Whereby the pin serves to hold the collar in retracted position, the end of the sleeve being castellated to provide a series of recesses in circularly spaced relation, and a projection provided on the abutting end of said collar for reception selectively in any one of said recesses When the collar is in locking position whereby positively to hold the sleeve against turning.

In Witness of the foregoing I aliix iny signature.

JOHN HERBERT ABRAMSON. 

